1. Field of the Invention
The present invention relates to an absorptive article such as a sanitary napkin, a pantie liner or a urine pad. More particularly, the invention relates to an absorptive article having wings to be folded back, when worn, to the lower side of the crotch portion of an underwear, and to a process for manufacturing the absorptive article.
2. Related Art
In recent years, various types of absorptive articles such as sanitary napkins, pantie liners or urine pads have been used for absorbing the discharges such as menses or urine. Most of these absorptive articles are provided with wings on the two longitudinally extending side portions. When the absorptive article is worn, the wings are folded back to the lower side of the crotch portion of the underwear to prevent the underwear edge portions from being blotted with the discharges. In general, these wings are provided with adhesion means for attaching them to the underwear. The absorptive article can be stably worn with little dislocation if its wings are attached and adhered to the lower side of the crotch portion of the underwear.
These wings are generally formed by protruding the members constructing the body of the absorptive article integrally, that is, the joint assembly of a back sheet and a top sheet sideways of the body of the absorptive article.
Where the joint assembly of the back sheet and the top sheet is used to form the wings, however, the absorptive article has to be manufactured such that: a laminate is formed by sandwiching an absorbent layer between a back sheet material and a top sheet material; and this laminate is trimmed out to form an elliptical or hour-glass body portion and wings. Therefore, the width sizes of the back sheet material and the top sheet material for use have to be made large to form the wings by cutting. Moreover, the unnecessary, waste portions to be cut out while leaving the body portion and the wingsshare excessively wide areas in the top sheet material and the back sheet material.
In some absorptive articles of the prior art, on the other hand, the wing members are formed separately from the members forming the body so that they may be given a function different from that of the top sheet. In Japanese Unexamined Patent Publication (Kokai) No. Heisei 6-47072, for example, there is disclosed a sanitary napkin in which the wing members and the side barriers (or the sideway leakage preventing cuffs) are made of a common member. This napkin can be manufactured by reducing one step of its manufacturing process because the members to be ordinarily attached separately of each other are made of the common member.
In Japanese Unexamined Patent Publication (Kouhyou) No. Heisei 9-511929, on the other hand, there is disclosed an absorptive article in which the wing members are easily folded downward along the edge portions of the crotch portion of an underwear. These wing members are provided with zones of different extensibilities to lower the stress which will arise at the folding time.
However, the structure, in which the wing members are made of a member different from that constructing the body, has a defect that the wing members easily come out from the body. In the aforementioned example, moreover, the wing members are jointed to the surface of the top sheet or back sheet of the absorptive article so that there is a limit to the enhancement of the joint strength between the wing members and the body. Since the wing members are wholly exposed to the surface of the absorptive article, moreover, their end portions are highly probably caught, when the absorptive article is worn, to leave the body.
On the other hand, the wing members are demanded to have functions such as an easy foldability along the edge portions of the underwear or an air-permeability. If the wing members and the side barriers are made of the common member as in the former example, for example, the wing members are hard to fold downward along the edge portions of the crotch portion of the underwear. Moreover, the side barriers are ordinarily made of an impermeable material, and the wing members have an air-permeability lowered to make the inside of the underwear stuffy if they are made of the same material. In the latter case, on the contrary, the wing members having the differently extensible zones could be made of an air-permeable material and are easily folded downward along the edge portions of the crotch portion of the underwear. In the presence of the differently extensible zones, however, the foldable areas of the wing members are so widened that the wing members are hard to fold on the predetermined lines in the manufacture process. As a result, it is difficult to raise the production efficiency.
An object of the invention is to provide an absorptive article having wing members jointed reliably.
Another object of the invention is to provide an absorptive article having wing members which can be easily folded downward along edge portions of a crotch portion of an underwear, and a process for manufacturing the absorptive article.
Still another object of the invention is to provide an absorptive article having wing members of excellent air-permeability, and a process for manufacturing the absorptive article.
A further object of the invention is to provide a process for manufacturing an absorptive article which can minimize the trimming loss of the materials to the least while having an excellent production efficiency.
According to the invention, there is provided an absorptive article comprising: a body including a liquid-permeable top sheet, a back sheet and an absorbent layer sandwiched between the top sheet and the back sheet; and wing members disposed on two side portions of the body and extending outwards in the widthwise direction from the body, wherein the wing members are jointed to the two side portions of the body while being sandwiched between the top sheet and the back sheet.
In the invention, the wing members are sandwiched between the top sheet and the back sheet so that they can be reliably jointed to the body while being prevented from coming out when the absorptive article is worn. In the invention, the wing members are made of a material different from those of the top sheet and the back sheet so that they can be given various functions.
Preferably, both the width size of joint regions between the top sheet and the wing members and the width size of joint regions between the back sheet and the wing members are at least 5 mm.
Preferably, at an intermediate region, to which the wing members are attached, of the body, the top sheet has a larger width size than that of the back sheet so that the joint regions between the top sheet and the wing members has a larger width size than that of the joint regions between the back sheet and the wing members.
Preferably, the wing members have a moisture permeability of no less than 10,000 g/m2 according to JIS-Z-0208. In this case, it is preferred that the width size of the joint regions between the top sheet and the wing members is at least 10 mm; that when the area of the joint regions between the top sheet and the wing members is assumed to be 1 (or 100 %), the substantial joint area in the joint regions between the top sheet and the wing members by an adhesive is at most 0.2 (or 20%); and that the top sheet and the wing members are partially welded and jointed. More preferably, a plurality of welded and jointed portions are extended in the widthwise direction and provided at intervals in the longitudinal direction such that at least one welded and jointed portion extends from the joint regions between the top sheet and the wing members to regions of only the wing members.
Preferably, the rigidity value of regions, in which the wing members, the top sheet and the back sheet are jointed together, according to the cantilever method is larger by at least 20 mm than that of a joint portion, in which the top sheet and the back sheet are jointed to each other without sandwiching the wing members, according to the cantilever method. In this case, the rigidity value of the wing members according to the cantilever method is preferably 50 to 150 mm in the MD and 30 to 100 mm in the CD.
Preferably, the wing members have an extensibility in the widthwise direction so that the shrinking force of the wing members as a whole for a strain of 10% is at least 5 gf when the wing members are uniformly extended in the widthwise direction all over the area of the longitudinal direction.
Preferably, the wing members have an extensibility in the widthwise direction so that the strain when extended to the limits in the widthwise direction is within a range of 10 to 40%.
Preferably, the wing members have a total-ray transmissivity of at least 20% according to the JIS-K-7105.
According to the invention, there is also provided a process for manufacturing an absorptive article including: a body including a liquid-permeable top sheet, a back sheet and an absorbent layer sandwiched between the top sheet and the back sheet; and wing members disposed on two side portions of the body and extending outwards in the widthwise direction from the body, comprising:
(a) a step of jointing wing member materials to two sides of a back sheet material;
(b) a step of placing an absorbent layer on the back sheet material before or after the step (a);
(c) a step of sandwiching the absorbent layer between a top sheet material and the back sheet material by feeding the top sheet material over the absorbent layer;
(d) a step of jointing the top sheet material and the back sheet material on the outer side of the absorbent layer; and
(e) a step of cutting off unnecessary portions of the back sheet material, the top sheet material and the wing member materials, to manufacture an absorptive article in which the body and the wing members are jointed.
According to this manufacture process, the unnecessary portion to be disposed during the manufacture, that is, the so-called xe2x80x9ctrimming lossxe2x80x9d is reduced, and the wing members can be simply attached to the body so that the process is excellent in the productivity.
At the step (a), the wing member materials are preferably jointed to the upper face of the back sheet material, and at the step (c), the wing member materials are preferably sandwiched and jointed between the back sheet material and the top sheet material.
At the step (d), the back sheet material and the top sheet material are preferably jointed by an adhesive.
The process preferably further comprises: between the step (d) and the step (e), the step of welding and jointing the top sheet material and the wing member materials.